| Re: [eigen] Matrix product crashes when compiled with MSVC 2010 in release |
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- To: eigen@xxxxxxxxxxxxxxxxxxx
- Subject: Re: [eigen] Matrix product crashes when compiled with MSVC 2010 in release
- From: Hauke Heibel <hauke.heibel@xxxxxxxxxxxxxx>
- Date: Fri, 13 Aug 2010 16:03:53 +0200
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On Fri, Aug 13, 2010 at 4:00 PM, Benoit Jacob <jacob.benoit.1@xxxxxxxxx> wrote:
> 2010/8/13 Hauke Heibel <hauke.heibel@xxxxxxxxxxxxxx>:
> Unfortunately, the patch creates a wrong result:
>
> +#if defined(EIGEN_VECTORIZE) && defined(_MSC_VER) && !defined(_WIN64)
> + const AccPacket tmp1 = ei_pmul(alpha,c);
> + const AccPacket tmp2 = ei_pmul(alpha,r);
> + r = ei_padd(tmp1,tmp2);
> +#else
> r = ei_pmadd(c,alpha,r);
> +#endif
>
> Here, the current code r=pmadd(c,alpha,r) does (in pseudocode):
>
> r = alpha*c+r.
>
> But your variant does instead:
>
> r = alpha*c + alpha*r
Ups, too hasty.